As used here, the phrase “distributed time-triggered protocol” means a communication protocol that enables a group of nodes to communicate using a time division multiple access (TDMA) scheme where the nodes employ a distributed clock synchronization algorithm to synchronize their local clocks to one another. One example of a distributed time-triggered protocol is the FlexRay time-triggered protocol developed by the FlexRay Consortium and described in detail in the FlexRay Protocol Specification V2.1 Rev. A and Protocol Specification V2.1. Rev. A Errata V1, both of which are incorporated herein by reference in their entirety.
The FlexRay protocol, as specified in the V2.1 Rev. A specification, does not incorporate a mechanism to synchronize a cluster of FlexRay nodes to an external time-base.
In addition, the FlexRay protocol, as specified in the V2.1 Rev. A specification, has known dependency vulnerabilities, such as protocol failure during start-up.
Moreover, in domains such as aerospace where formal design assurance is expected (for example, in accordance with the Design Assurance Guidance for Airborne Electronic Hardware DO-254 standard published by RTCA, Incorporated) the feasibility and costs of certifying complex commercial intellectual property (IP) cores—such as FlexRay IP cores—comprise a significant risk. Although COTS certification arguments (for example, arguments for validation based on use) may be viable for standalone integrated circuits and IP cores integrated and produced in mass volume, in the aerospace domain where IP cores are often embedded into aerospace-specific custom designs, such arguments may be compromised.